Traditionally, a robot controller of an industrial robot is provided with servo controllers for controlling the positions of the motors driving the motion of the manipulator. Meanwhile, each joint motor transmits coordinate signals to the robot controller to determine whether the trajectory of the robot arm matches an expectation or not. If the trajectory of the robot arm does not match the expectation, the user normally edit the commands over and over again through programming languages or application programs, and edit the movement path of the robot arm according to the user's commands.. However, such manner is tedious and time consuming, and lacks intuitive programmability. That is, there is no intuitive input interface existing between the robot arm and the user, and conventional programming system does not allow the user to edit the movement path of the robot arm through intuitive operations. These are the current problems that need to be resolved in the design and manufacturing of robot arms.